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Subject: Re: [OMPI users] Can 2 IB HCAs give twice the bandwidth?
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2008-10-19 06:27:05

On Oct 18, 2008, at 9:19 PM, Mostyn Lewis wrote:

> Can OpenMPI do like Scali and MVAPICH2 and utilize 2 IB HCAs per
> machine
> to approach double the bandwidth on simple tests such as IMB PingPong?

Yes. OMPI will automatically (and aggressively) use as many active
ports as you have. So you shouldn't need to list devices+ports --
OMPI will simply use all ports that it finds in the active state. If
your ports are on physically separate IB networks, then each IB
network will require a different subnet ID so that OMPI can compute
reachability properly.

Jeff Squyres
Cisco Systems